An image detector in one endoscope can have a responsiveness that is different than the responsiveness of an image detector in another endoscope, even if the image detectors are similarly configured and were produced using the same process. Even a single image detector of an endoscope can have individual pixels that respond differently to incident light relative to other pixels of that image detector. Often, the variations in responsiveness can be caused by, for example, different operating conditions and/or manufacturing variations (e.g., semiconductor processing variation). Furthermore, the responsiveness of an image detector of an endoscope can change as the image detector and/or endoscope ages. Variations in the responsiveness of image detectors can be undesirable in many endoscopic applications (e.g., clinical applications).
Known calibration procedures can be used to equalize and normalize the responsiveness of image detectors of endoscopes (e.g., pixel-to-pixel, endoscope-to-endoscope). These calibration procedures, however, can be performed using a disposable endoscope cover that cannot be used more than once. In addition, these disposable endoscope covers can be limited to a single target pattern. Alternatively, the calibration procedures can be performed using a reusable calibration cup (or cover) that can degrade with age and when not cleaned properly. In addition, the cup can be limited to use with a uniform white field with no target pattern. Thus, a need exists for a multi-use endoscopic calibration unit that can have multiple targets and related methods.